Commutator.



H. W. TURNER.

CQMMUTATOR. APPLICATION FILED MAR. 2 I915.

. 1 1 57 9 1 2 Patented 0st. 26, 1915.

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.UNITED STATES PATENT OFFICE.

HARRY W. TURNER, OF GLENVILLE, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

COMMUTATOR.

Specification of Letters Patent.

Patented Oct. 26, 1915.

Application filed March 2, 1915. Serial No. 11,459.

To all whom it may concern:

Be it known that I, HARRY W. TURNER, a citizen of the United States, residing at Glenville, county of Schenectady, State of New York, have invented certain new and useful Improvements in Commutators, of which the following is a specification.

My invention relates to conimutators for use-with dynamo-electric machines, and has for its object an, improvement in such devices.

'More specifically my invention relates to an improved form of insulation for commutators, and I accomplish the object of my invention by providing an insulation which consists of non-hygroscopic and preferably metalsheets enameled with some form of suitable insulating enamel.

The novel features of my invention are pointed out with more particularity in the claims annexed to and forming a part of this specification.

For a further understanding of my invention, reference may be had to the accompanying drawing, in which Figure 1 is a side elevation partly in section of a commutator constructed in accordance with my invention; Fig. 2 is a partial end elevation showing a portion of the commutator bars, with the insulation between them; Fig. 3 is a partial end elevation showing a portion of the commutator bars and a preferred form of insulation, and Fig. 4 is a perspective view partly in section of a portion of the insulation which I employ.

Referring first to Fig. 1, 1 is a portion of the shaft of a dynamo-electric machine, upon which is mounted the commutator shell 2. This shell is provided at one end with an annular clamping jaw 3.

At the opposite end of the shell and resting upon the same is an end member 4, also with a clamping jaw, and secured in place by the nut 5 threaded upon the commutator shell.

' the inner sheets.

any particular form but may be used with any of the well known forms of construction.

Referring to Fig. 2, the commutator bars 6 have between them sheets of my improved insulation 8, the figure showing two such sheets, but it will be understood that any desired number may be employed. This insulation (see Fig. 4) consists of a sheet of suitable material 9 formed with a coating of insulating enamel 10 on each side of the sheet. To avoid the absorption of oil, water, etc., which may tend to injure the commutator, I prefer to form this sheet of nonhygroscopic material, and in the preferred embodiment of my invention I employ a metal, such as copper.

Thin copper sheets about 5 mils in thickness are enameled with a suitable insulating enamel on each side, one or more layers of enamel being used. dependent upon the voltage for which the commutator is constructed. After the sheets have been enameled and the insulation formed, it may then be cut to fit the commutator bars, and, if desired, in the usual manner may be made the same contour as the bars. The cut portions may then be built up with the commutator bars to form the commutator in the usual manner.

When enameled sheets of copper or other suitable metal are used, as shown in Fig. 2, since the edges of the commutator bars and the sheets are substantially in line, there is a tendency for the commutator to become pitted. I, therefore, prefer to insulate the' bars in the manner shown in Fig. 3, where the bars 6 have the insulation bent around the two sides and the inner surfaces of the bars. As shown in the figure, two sheets of insulation are bent around each bar. The edges of the inside sheet do not extend in line with or up to the outer surfaces of the bars upon which the brushes rest and the edges of the second sheets do not extend to the edges of The grooves thus left on the surface of the commutator may be filled with some suitable insulation 11 in order to give the commutator a smooth and even surace.

By the arrangement as shown in Fig. 3, the surface of the commutator will not tend to become pitted, as the brushes will not come in contact with the metal sheets, and, by the staggered arrangement of the edges of the folded sheets of insulation, if for any reason in cutting the insulation portions of the metal should be dragged over the edges of the adjacent enamel, there will be no possibility of a short-circuit between adjacent commutator bars inasmuch as such portions of the metal on the shorter pieces of insulation will be insulated from the metal sheets of the inner layers of the insulation by the enamel on the sides of the said inner layers.

It will be understood that While this feature of staggering the edges of the insulation is not essential, for the reasons given above I prefer to employ it. Also that While only two sheets of insulation are shown as bent around each bar, any desired number may be employed and the usual insulating ring, if desired, may be employed between the commutator shell and the inner edges of the bars and the insulation surrounding the same. a a

In accordance With-the provisions of the patent statutes, I have described the princi ple of operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof; but I desire to have it understood that the apparatusshown is only illustrative, and that the invention can be carried out by other means.

hat I claim as new, and desire to secure by Letters Patent of the United States, is

1. A commutator comprising a plurality of commutator bars, means for supporting the bars, and an insulation for the bars comprising sheets of non-hygroscopic material coated with an insulating enamel.

2. In a commutator, a pair of adjacent conductor bars and an insulation between them comprising sheets of non-hygroscopic material coated with an insulating enamel.

3. In a commutator, a pair of adjacent conductor bars and an insulation between the bars comprising metal sheets coated with an insulating enamel.

4. In a commutator, a pair of adjacent conductor bars and a plurality of insulating members therefor comprising metal sheets coated With an insulating enamel and bent around the sides and the inner surfaces of the bars.

5. In a commutator, adjacent commutator bars, sheets of insulation consisting of sheets of metal coated with an insulating enamel bent around the two sides and the inner surfaces of the bars, the edges of the sheets not extending to the outer surfaces of the bars nor the edges of adjacent sheets extending in line with each other, and an-insulation filling the grooves thus formedbetween the bars.

In witness whereof, I have hereunto set my hand this 1st day of March, 1915.

HARRY IV. TURNER.

Witnesses:

ANsoN l/V. ROGERS, HELEN ORFORD. 

